Linear activated drug dosing pump system

Abstract

A novel embodiment of a pump system, for example, of the type that would be used in a wearable drug delivery system, comprises dual linear-actuated plungers disposed in a pump chamber. The plungers are coupled to a leadscrew having both left-hand and right-hand threads such that rotation of leadscrew in a first direction moves the plungers together and rotation of leadscrew in a second, opposite direction moves the plungers apart. Movement of the plungers away from each other draws one or more doses of a liquid drug from a reservoir into the pump chamber, while movement of the plungers together forces liquid drug to a patient interface for delivery to the patient.

1 . A pump system comprising:
 a pump chamber comprising a tube-like structure having a first end and a second end opposite the first end;   a threaded leadscrew, extending along a longitudinal axis of the pump chamber;   a plunger coupled to the leadscrew via the threading;   an inlet port fluidly coupled to a reservoir; and   an outlet port fluidly coupled to a patient interface;   wherein rotation of the leadscrew causes the plunger to move away from the first end of the pump chamber, thereby drawing a liquid from the reservoir into the pump chamber; and   wherein rotation of the leadscrew in a second, opposite direction causes the plunger to move toward the first end of the pump chamber, thereby forcing the liquid from the pump chamber to the patient interface.   
     
     
         2 . The pump system of  claim 1 , wherein the first end comprises an end wall. 
     
     
         3 . The pump system of  claim 2 , wherein the inlet port and the outlet port are each defined in a sidewall of the pump chamber adjacent to the end wall. 
     
     
         4 . The pump system of  claim 2 , wherein the plunger is configured so that, when the plunger is adjacent to the end wall, the plunger blocks the inlet port and the outlet port. 
     
     
         5 . The pump system of  claim 2 , wherein the plunger is configured to move away from the end wall to create a negative pressure in a volume between the plunger and the end wall to draw the liquid into the volume. 
     
     
         6 . The pump system of  claim 2 , wherein the plunger is configured to move towards the end wall to create a positive pressure in a volume between the plunger and the end wall to expel the liquid through the patient interface. 
     
     
         7 . The pump system of  claim 6 , further comprising a one-way valve configured to prevent the liquid from returning to the reservoir as the plunger moves toward the end wall. 
     
     
         8 . The pump system of  claim 1 , further comprising a one-way valve configured to prevent a fluid from a patient from being drawn into the pump chamber from the reservoir. 
     
     
         9 . The pump system of  claim 1 , wherein the reservoir is coupled to the inlet port via an inlet conduit. 
     
     
         10 . The pump system of  claim 1 , wherein the outlet port is coupled to the patient interface via an output conduit. 
     
     
         11 . A method comprising:
 placing the pump system according to  claim 1  in a start position in which the plunger is in contact with an end wall of the pump chamber; and   moving the plunger away from the end wall to draw the liquid from the reservoir into a volume between the end wall and the plunger.   
     
     
         12 . The method of  claim 11 , wherein moving the plunger away from the end wall comprises rotating the lead screw in the first direction. 
     
     
         13 . The method of  claim 11 , further comprising receiving a control signal requesting a delivery of one or more units of the liquid to a patient. 
     
     
         14 . The method of  claim 13 , further comprising moving the plunger toward the end wall to force the one or more units of the liquid to the patient interface. 
     
     
         15 . The method of  claim 14 , wherein moving the plunger toward the end wall comprises rotating the lead screw in the second direction. 
     
     
         16 . The method of  claim 11 , further comprising:
 determining that the volume is empty; and   in response to the determining, moving the plunger away from the end wall to load an additional quantity of liquid into the volume.   
     
     
         17 . The method of  claim 11 , wherein the plunger comes into contact with the end wall at an end of each cycle of liquid delivery.